XVI International Botanical Congess

The subfamily Eriogonoideae (Polygonaceae) consists of 17 genera and 316 species restricted to N. and S. America. Circumscription of the subfamily has been stable since its inception, however, relationships within the subfamily and generic definitions have been variable. Most taxa are contained within Eriogonum (240 species) and Chorizanthe (51 species). The remaining 15 genera are small and limited in distribution. Data from studies of vegetative morphology, inflorescence structure, floral and fruit morphology, and pollen ultrastructure were used in a cladistic analysis to assess the monophyly of Chorizanthe, interspecific relationships within Chorizanthe, and intergeneric relationships in the Eriogonoideae. In addition, the resulting phylogeny was used to assess evolution of morphology within the subfamily.